ForHosting KIT · Developer Utilities

Base64url encoder and decoder

This Base64url encoder converts plain text into URL-safe Base64 and decodes Base64url strings back to UTF-8 text using the RFC 4648 section 5 alphabet.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Unlike classic Base64, the output never contains plus or slash characters and never ends with equals padding, so tokens survive query strings, path segments, and JSON without extra escaping. Pick encode to turn a message, claim set, or configuration string into a compact Base64url payload, or pick decode to recover the original text from a URL-safe token you already hold. The engine is fully deterministic: the same input and mode always produce the same result, with no network calls, no random salts, and no date-dependent shortcuts. Common checks include encoding hello world to aGVsbG8gd29ybGQ and decoding that string back to the original phrase. Use it free in the browser for JWT practice, OAuth state values, and API fixtures, or call the API at $0.002 per successful request when pipelines need reproducible Base64url transforms in CI and backend services.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

How do I use this capability?

Complete the fields above and run it on this page. The form highlights anything that needs attention.

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/enc/base64url

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/enc/base64url \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text":"hello world"}'

const res = await fetch("https://api.kit.forhosting.com/enc/base64url", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "text": "hello world"
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/enc/base64url",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "text": "hello world"
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/enc/base64url", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"text":"hello world"}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"text":"hello world"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/enc/base64url", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "text": "hello world"
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "enc.base64url",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Read the full KIT documentation →

Run — free